Question: Pamela drove her car $99$ kilometers and used $9$ liters of fuel. She wants to know how many kilometers $(k)$ she can drive with $12$ liters of fuel. She assumes the relationship between kilometers and fuel is proportional. How many kilometers can Pamela drive with $12$ liters of fuel?
Explanation: We're dealing with a proportional relationship, so each ratio of kilometers to liters must be equivalent. Let's use a table to see how far Pamela can drive with one liter of fuel. ${11}$ $\longrightarrow$ ${1}$ ${99}$ $\longrightarrow$ ${9}$ $ \times {\dfrac{1}{9}}$ $ \times {\dfrac{1}{9}}$ ${{km}}$ $\longrightarrow$ ${{L}}$ Pamela can drive ${11} \text{ km}$ on one liter of fuel. Now, we can use this rate to solve for how many kilometers Pamela can drive with $12$ liters of fuel. $k$ $\longrightarrow$ ${12}$ ${{11}}$ $\longrightarrow$ ${1}$ $ \times {12}$ $ \times {12}$ ${99}$ $\longrightarrow$ ${9}$ ${{km}}$ $\longrightarrow$ ${{L}}$ $k={11}\times12=132$ Pamela can drive $132 \text{ km}$ with $12$ liters of fuel.